Modern vehicles, specifically hybrid or electric vehicles, have on-board systems incorporating a high voltage (HV) system branch with a service voltage of several hundred volts.
However, for a person, specifically a child, a voltage exceeding 60 Volts (V) is life threatening. An HV system branch with a service voltage exceeding 60 V is therefore electrically insulated from the rest of the on-board system or from the vehicle bodywork, in order to eliminate the hazard to persons.
In case of technical defects in the on-board system or operating errors, a “fault current” can flow from the HV system branch through the human body. If the electrical insulation between the above-mentioned HV system branch and the rest of the on-board system or the vehicle bodywork is intact and sufficiently high, the fault current strength is limited to a non-hazardous value for persons.
However, if the electrical insulation is not sufficiently high, a fault current with a rating of several milliamps can flow through the human body, which can be life threatening to persons.
As such, in order to avoid such life-threatening fault currents from the outset, electrical insulation in the on-board system must be constantly monitored and potential hazards identified at the earliest opportunity.